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The authors report on the organic field-effect transistors based on copper phthalocyanine with a inserted layer of molybdenum oxide (MoO3). After applying a positive gate voltage of 100 V, the threshold voltage had a large shift from -11.8 to +66.2 V and the device operating model was changed from the enhancement model into the depletion one. A possible mechanism is believed to be originated from the stored charges in the interface between the thin MoO3 layer and the active layer. Largely reversible shift in the threshold voltage and retention time were also obtained in the devices by the programs used. [ABSTRACT FROM AUTHOR]

The authors report excellent white organic light-emitting diodes (WOLEDs) made of 9,9bis[4-(di-p-tolyl)aminophenyl]-2,7-bis(diphenylamino)fluorene (TADPF) or 9,9-bis[4-(di-p-tolyl)aminophenyl]-2,7-bis(9-carbazolyl)fluorene (TAKF). The superposition of a yellow emission coming from the TADPF or TAKF electromer and a blue emission originating from bis(2-(2-hydroxyphenyl)benzothiazolate)zinc gives rise to a pure white-light emission. The multilayer device using TADPF shows a maximum luminance of 5123 cd/m2, a current efficiency of 2.8 cd/A, and Commission Internationale d’Eclairage chromaticity coordinates of (0.33, 0.33). This result is the optimal for WOLEDs based on electromers so far reported. [ABSTRACT FROM AUTHOR]

We demonstrate modification of the indium tin oxide (ITO) surface with an ultrathin layer of hexadecafluorocopper phthalocyanine (F16CuPc) can significantly enhance hole injection as a result of the formation of an interfacial dipole layer. The dipole layer produces a surface potential shift, which reduces the hole injection energy barriers and thus improves the hole injection efficiency. The devices with anode modification exhibit significantly enhanced luminance efficiencies and dramatically decreased operation voltages, compared to devices with the bare ITO anode. The minimum turn-on voltage of 2.6 V and the maximum efficiency of 5.1 cd/A are achieved. [ABSTRACT FROM AUTHOR]

Employing 5,5′-bis-biphenyl-dithieno[3,2-b:2′,3′-d]thiophene (BPDTT) as semiconducting layer and poly(vinyl alcohol) (PVA) as gate dielectric layer, we have fabricated organic thin-film transistors. These devices exhibit excellent field-effect performances with a high mobility of up to 0.6 cm2/V s and a very low operating voltage (<1 V) at room temperature. The single crystal of BPDTT was grown and analyzed. The high performances are mainly attributed to the close herringbone packing of BPDTT molecules and the high homogeneity between PVA and BPDTT molecules. [ABSTRACT FROM AUTHOR]

We present a method of fabricating noncoplanar channel organic field-effect transistors (OFETs) by a conventional photolithographic technique. Using this method, OFETs with micrometer critical features in slanting configurations and submicrometer critical features in vertical configurations were fabricated. The critical channel length over 1 μm was controlled by the patterning technique, while the one of 0.5 μm was defined by the thickness of an insulating layer between the drain and source electrodes. Also, we demonstrate that the OFETs containing two different metals as source and drain electrodes, respectively, are easily realized. All the OFETs based on copper phthalocyanine exhibit a high performance. [ABSTRACT FROM AUTHOR]

We fabricate single-walled carbon nanotube field-effect transistors (SWNT FETs) with a simple, low-cost, high-efficiency, and solution-based orientational self-assembly method. The SWNT was first functionalized with thiol groups, then suspended in an N,N-dimethylformamide solution, and finally self-assembled on predefined gold contact pads by an orientational N2 blow. A relatively high mobility of 9.2×102 cm2/V s and an on/off ratio greater than 105 at a bias voltage of -1 V have been achieved as a result of directly covalent interaction between end-thiolated SWNT and gold contacts, which favors the fabrication of SWNT FETs as compared to the SWNT FETs bearing the similar geometry but relies on random deposition. Therefore, this orientational self-assembly approach should be a valuable tool in the mass fabrication of high-performance SWNT FETs and SWNT-based molecular-scale electronic devices. [ABSTRACT FROM AUTHOR]

We report an efficient blue light-emitting diode (LED) using N, N′-bis(1-naphthyl)-N, N′-diphenylbenzidine as an emitting layer and tetra(β-naphthyl)silane (TNS) as a hole-blocking layer (HBL). We find that the hole-blocking performance, thermal stability, and film-forming ability of TNS are improved over those of the prototypical hole-blocking material 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The device that used TNS as the HBL exhibits a narrower light emission and higher current efficiency (2.5 cd/A) as compared with the device containing BCP as the HBL. TNS should be promising as an excellent hole-blocking layer in LEDs. [ABSTRACT FROM AUTHOR]

We report the effects of a metal chelate, bis[2-(2-hydroxyphenyl)benzothiazolate]zinc [Zn(BTZ)2] and 8-tris-hydroxyquinoline aluminum (Alq3) used as electron-transporting layers, and various cathodes on electroluminescent and current-voltage characteristics of a polymer light-emitting diode with phenyl-substituted poly(phenylene vinylene) as an emissive layer. We find that the metal chelate layers also play a role in hole blocking. For a double-layer device with the structure of indium-tin oxide (ITO)/polymer/Zn(BTZ)2 or Alq3/Al, the metal chelate layer lowers the hole current and improves the electroluminescent properties. Inserting a LiF layer between the metal chelate layer and the Al cathode enhances the electron injection and improves the elctroluminescent efficiency. The device with the structure of ITO/polymer/Zn(BTZ)2/Alq3/LiF/Al can reach the highest luminous efficiency of 5.0 cd/A. [ABSTRACT FROM AUTHOR]

Field-effect transistors (FETs) based on an individual CN[sub x]/C nanotube (NT) were fabricated by focus ion-beam technology. The nanotube transistors exhibited n-type semiconductor characteristics, and the conductance of nanotube FETs can be modulated more than four orders of magnitude at room temperature. The electron mobility of a CN[sub x]/C NT FET estimated from its transconductance was as high as 3.84×10[sup 3] cm[sup 2]/V s. The n-type gate modulation could be explained as due the effect of bending of the valence band in the Schottky-barrier junction. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Features an efficient light-emitting diodes using a binaphthalene polymer as the emissive layer and a fluorinated copper phthalocyanine as the electron injecting/transporting layer. Twisted, nonplanar backbone with two hexyloxy side groups; Energy levels; Brightness, luminous efficiency and quantum efficiency of a light-emitting diode with aluminum electrode.